I think Hirsch is basically right here, but there are two things I don’t like. 1) The article overemphasizes vocabulary to the exclusion of other factors. I’m suspicious of any solution to a complex problem that relies on a single factor. 2) He errs by diving in to the SAT score issue in the beginning. The value of the SAT and whether it measures anything of significance is hotly debated. It’s not a settled matter as Hirsch claims.

But I agree with his core point. Vocabulary is not only a proxy for other types of knowledge, it’s a key factor in how we process things cognitively. And the best way to increase one’s vocabulary is contextually.

Does anyone know the percentage of words an ordinary person knows in an ordinary paperback family dictionary? It must be over 90%. Has this ever been researched? Dictionary compilers are constrained to include words like cat, eat, buy, talk, etc which no native-speaker ever looks up except to settle spelling disputes maybe. (I once won a shilling off my dad who was convinced it was longtitude which I heard a BBC presenter, Kate Humble, use a couple of years ago.)

Vocabulary counts are notoriously unreliable. How you decide whether a word is distinct from another can often be very tricky. (Is a computer “mouse” the same word as the rodent? What about inflections? Is “fun” both a noun and an adjective, or just a noun that sometimes acts adjectivally?)

But the common number trotted out is that the “average” (whatever that means) educated English-speaker knows about 20,000 words. There are, of course, some people who know twice or even three times this number of words. A pocket dictionary will contain something like 45,000 words. Merriam-Webster’s Pocket Dictionary has some 40,000 words.

But it’s not as simple as comparing the numbers. After including the few thousand most commonly used words, the lexicographers will tend to include words fall into several categories, such as 1) easily misspelled; 2) often misused; 3) difficult words but ones that are likely to be encountered in literature and newspapers, including common jargon of particular disciplines. And what words are included may change with the intended audience; a dictionary aimed at ESL students will cover a different range of words than a standard reference. So there’s likely to be less overlap than a simple count would indicate.

Those are good points but I remember trying to shoe-horn “esconced” into school homework and failing to find it in my dictionary. Now, google says “Showing results for ensconced” and my spellchecker sorted it too. It used to be hard to look up some words you weren’t sure of the spelling of and still is if you don’t have an internet connection.

My excellent and massive Reader’s Digest Reverse Dictionary has a 10,000-word LEXICON OF DIFFICULT WORDS at the back. Has anyone ever published a standalone version of this idea? I’d certainly favour a paperback one for my attache case over a bulkier one also containing thousands of words like fish and book. It must be a nightmare for lexicographers deciding which words to include or omit in various dictionaries with different target readerships.

I’ve heard this as well, but does anyone know how this was determined?

I don’t know. I’ve never bothered to check as I’ve always thought that any such count would be highly subjective. Here’s what Tom McArthur’s The Concise Oxford Companion to the English Language has to say on the subject:

It is not unusual, however, to find assertions that the average person makes use of, for most purposes, fewer words than Shakespeare: perhaps 15,000 items. If, however, the count starts with the c. 3,000 words in lists used for the early stages in the learning of English as a foreign language, such a total is soon exceeded simply by adding compounds, derivatives, phrasal verbs, abbreviations, and fixed phrases commonly associated with those c. 3000 words. [...] All or most of such items are well within the range of most users of English educated to around 16–18 years of age. A crude extrapolation of 10 x 3,000 suggests that such people are familiar with some 30,000 such items, or twice the above estimate. Bringing in many everyday words not in the basic 3,000, and applying the same multiplier, soon takes the average person to double or treble this number without discomfort, every personal “list” of words and word-like items differing from every other.

This [one’s reported result; the numbers discussed in the previous thread] is the estimated number of entries in a standard dictionary for which you know at least one definition.

This number does not include word derivations (e.g. “quickly,” derived from “quick,” does not count as a separate word). And while it does count compound words (like “air conditioning"), it does not include phrases or expressions (like “food for thought").

Thanks for taking the test! Based on over 200,000 participations so far, we’ve got some initial statistics already. Most Native English adult speakers who have taken the test fall in the range 20,000–35,000 words.